I was about to link you
HERE, for a glimpse of what's available in model train hobby shops. They stock perforated sheet, though usually very fine photo-etched stuff. Too fragile, I guess.
Larger screens litter scrapyards. I'm positive you can pick up some undamaged stainless steel screen or perforated sheet, priced
by weight.

Bring a screwdriver, and just dive into to the first monstrosity of used hospital machinery you see. If it's metal, it's there. I once met a friggin' 727 jet engine, perched on shower doors and defective scooters. More fun than mail-order.